As a very common malignant tumor of the respiratory system, lung cancer may have respiratory failure before death, so the symptoms three days before death may mainly include cough, coughing and persistent aggravation of chest tightness, accompanied by heavier hemoptysis, chest pain and chest tightness, which are the manifestations of the respiratory system. Of course, lung cancer patients may also have multiple metastases before death, and will have symptoms of corresponding metastatic sites. Liver metastasis of lung cancer will show abdominal distension, abdominal pain, ascites, jaundice, complete inability to eat, severe malnutrition, etc. Patients may have hypoproteinemia, severe anemia, generalized swelling, etc. If lung cancer develops brain metastasis, there will be symptoms of increased intracranial pressure, such as dizziness, headache, nausea, vomiting, etc. Bone metastases may show pathological fractures and more severe bone pain, and patients in advanced stages can only strengthen the companionship to minimize the pain before they die.